Photo-Catalytic Activity of ZnO Supported on H-ZSM-5 Zeolite to Reduce Cr(VI) from Aqueous Solutions

Document Type : Original Article

Authors

1 Social Determinants of Health (SDH) Research Center” and “Environmental Health Department, Health Faculty”, Kashan University of Medical Sciences, Kashan, Iran

2 Chemical Engineering Faculty, Sahand University of Technology, Sahand New Town, Iran

Abstract

Aims The application of photocatalytic processes to remove heavy metals in aqueous
solutions and industrial wastewater are regarded as extremely effective, clean and without
producing waste methods. The goal of the present study was to investigate the photocatalytic
activity of ZnO based on H-ZSM-5 zeolite support.
Materials & Methods ZnO/H-ZSM-5 composite synthesized by impregnation method
successfully, and photo-reduction of Cr(VI) was investigated via this composite in present of
UV light irradiation. The prepared composite was characterized by X-ray Diffraction (XRD)
and Field Emission Scanning Electron Microscopy (FESEM). Data was analyzed by repeated
measurement statistical test.
Findings ZnO/H-ZSM-5 (79.5%) had better removal photo-reduction activity than pure
H-ZSM-5 (8.7%; p=0.003) zeolite and ZnO (58.8%; p=0.003). The initial concentration of
Cr(VI) was a highly influential factor in photo-reduction of Cr(VI); In the way that when the
initial concentration increased from 10 to 40mg/l, the photo-reduction percentage decreased
from 92.5 to 57.7% in constant operational conditions (p=0.001).
Conclusion ZnO/H-ZSM-5 composite has higher removal photo-catalytic activity than pure
ZnO and HZSM-5 zeolite. Photo-reduction of Cr(VI) by ZnO/H-ZSM-5 composite is an efficient
technology for the treatment of water and wastewater containing high concentration of Cr(VI).

Keywords